Apart from pelvic and back pain, there are also other signs of cervical cancer one should watch out for, and consult their gynecologist if they experience any such symptoms. These include abnormal vaginal bleeding which can happen after sex, in-between periods or may also be indicated by heavier-than-usual flows during period.
You should also consult your doctor if you observe any changes in your vaginal discharge. However, it can be due to other reasons as well, and not cancer necessarily. Experiencing pain during sex may also be an indication of cancer.